LOYOLA SCHOOL

(CBSE)
SREEKARIYAM
THIRUVANANTHAPURAM- 695 017

PHYSICS PROJECT
2024- 2025

Name: ………………………………………………………………

Class: ………………….. Reg.No: ……………………………………...

 LOYOLA SCHOOL
(CBSE)
SREEKARIYAM
THIRUVANANTHAPURAM- 695 017

CERTIFICATE
This is to certify that this is a bonafide report of the Project in Physics submitted by

………………………………………………………… as per the syllabus of SSCE (class

XII) during the academic year 2024-2025.

…………………… ………………….
Teacher in-charge Principal

……………………
Examiner’s Signature
 MAPPING
OF
MAGNETIC FIELD
 Index

1. Acknowledgement
2. Aim
3. Introduction
4. Earth’s Magnetic Field
5. Experiment
6. Observation
7. Conclusion
8. Bibliography
 Acknowledgement
I thank God Almighty for showering his blessings during
the course of this project. I thank our Principal Fr. Roy
Alex S.J., for providing us with all the necessities we
needed during the project. I would also like to express my
gratitude to our Physics teacher Mrs. Rosmy Thomas for
her guidance and support that was very much beneficial
to our project. I would like to thank our Lab Assistant Mr.
Sudheesh for helping us with the technical aspects. I
would also like to thank our parents for their kind
support.
 Aim
To find the magnetic field lines around a magnet by
the method of magnetic field mapping.
 Introduction
Magnetism is a class of physical phenomena that are medicated
by magnetic fields. Electric current and the magnetic moments of
elementary particles gives rise to magnetic fields, which acts on
other current and magnetic moments. Every material is
influenced to some the extent by magnetic fields. The most
familiar effect are permanent magnets, which have persistent
magnetic moments caused by ferromagnetism. The prefix Ferro
refers to iron, because permanent magnetism was first observed
in a form of natural iron ore magnetic, 𝐹𝑒3 𝑂4 .
Most materials do not have permanent magnets. Some are
attracted to the magnetic field (diamagnetism); others have a
more complex relationship with an applied magnetic field (spin
glass behaviour and anti-ferromagnetism). Substances that are
negligibly affected by magnetic fields are known as non-magnetic
substances. These include copper, aluminium gases and plastic.
Pure oxygen exhibits magnetic properties when cooled to a liquid
state. The magnetic state (or magnetic phase) of the material
depends on temperature and other variables such as pressure
and the applied magnetic field. Magnetism is a force of nature,
which causes special kinds of objects to attract each other.
The Earth’s Magnetic Field
Earth's magnetic fields, also known as the geomagnetic field, is
the magnetic field that extends from the Earth's interior out into
space.
Roughly speaking it is the field of a dipole currently titled at an
angle of about 10° with respect to Earth's rational axis, as if there
were a magnet placed at that angle at the centre of the Earth.
Unlike a bar magnet, Earth's magnetic field changes over time
because it's generated by a geodynamo (in Earth's case, the
motion of molten iron alloys in its outer core). While the south
and north magnetic poles are usually located near the geographic
poles, they can wander widely over geological time scales, but
sufficiently slowly for ordinary compasses to remain useful for
navigation.
However, at irregular intervals averaging several hundred
thousand years, the Earth's field reverses and the north and
south magnetic poles relatively abruptly switch places. These
reversals of the geometric poles leave a record in rocks that are
of value to paleomagnetists in calculating geomagnetic fields in
the past. Such information in turn is helpful in studying the
motions of continents and ocean floors in the process of
tectonics. The magnetosphere is the region above the Earth's
magnetic field in space. It extends several tens of thousands of
kilometres in to space, protecting the Earth from the charged
particles of the solar wind and cosmic rays that would otherwise
strip away. The upper atmosphere, including the ozone layer
protects the Earth from harmful UV radiation.

This Photo by Unknown Author is

Magnetism is all around you. You can find it in the most
common places like the magnet on your refrigerator. The force
of magnetism flows from one pole to another.
A pole is a point where the force is pointed. The force of
magnetism causes the material to point along the direction the
magnetic force points. This means that the force has direction.
The force is represented by lines, which point from the positive
poles to the negative poles of the magnet.
It forces small pieces of iron to live up in the direction the
magnetic force points. The lines represent what is called the
magnetic field of the magnet. The magnetic fields are strongest
where the lines of force come together, and is weakest when
the lines of forces are apart.
A magnet is surrounded by a magnetic field. The field has both a
Northside, and a South side. This field is strongest when the
lines of force are closely spaced and weakest when widely
spaced.
Flux lines are the lines that determine how current flows
throughout a magnet. They are circular lines, which run around
the magnet. It is determined in which direction a current is
flowing by using a series of left-hand rules. Each magnet has its
own flux shape and rule.
Magnetism and electricity are very closely related. When
speaking of them together they are spoken of as an
electromagnetic force. There are three main factors that must
be thought of when realizing that magnetism and electricity are
related. These are
a) Moving electric charges produce magnetic fields.

b) Magnetic fields exert forces on moving electric charges.

c) When you charge magnetic fields in the presence of electric

charges it causes a current to flow.

Magnetism is present throughout the world. It is used in

electronics, medicines, generators, and in so many other things.
 Experiment
MAPPING OF MAGNETIC FIELD
MATERIALS AND APPARATUS
The given bar magnet compass needle, brass fixing pins,
drawing board, drawing paper etc.

PROCEDURE
TO DRAW THE MAGNETIC MERIDIAN
A Sheet of drawing paper is fixed on the drawing board and a
straight line is drawn symmetrically on the paper. The compass
needle is placed on the line. The drawing board is slowly turned
till the line becomes parallel to the magnetic needle always
coming to rest along the magnetic north- south direction, the
line is along the magnetic meridian. The outline of the drawing
boards is drawn on the table with chalk. Hereafter the board
should not be disturbed. A short straight line with an arrow of
the magnetic north of the Earth.
TO DRAW THE LINES OF FORCE
The bar magnet is placed on the paper on the North with its axis
in the magnetic meridian, with its North Pole pointing Earth's
magnetic north.
The dotted line should become the equatorial line of the
magnet. The outline of the magnet is drawn on the paper. The
compass needle is placed near the north pole of the magnet
and a dot is out against the north pole of the needle. The
compass box is moved so that its south pole is against the dot.
Another dot is put against the north pole of the needle and the
process is repeated to get a number of dots. The dots are joined
together with smooth line. These are lines of force.
A number of such lines of force are also drawn. The general the
pattern is shown in the figure.
Arrow marks are put on the lines to show the directions of the
lines of force. It was found that there are two points N1 and
N2 ,symmetrically situated on either side of the magnet on the
equatorial line where there are no lines of force.
The compass needle placed on these points will remain in any
direction. These are null points. The distance 2d between the
two null points is measured and the distance of the null point
from the centre of the bar, the magnet is found out. The length
2l of the magnet is measured using a meter scale. From this,
half of the length of the magnet is determined.
At null points, the horizontal intensity BH of the Earth's
magnetic field and the field due to the bar magnet are equal
and opposite.

3
7 2 2 )2
i.e., B𝐻 = 10 𝑚 − (𝑑 + 𝑙 𝑚
= B𝐻 (𝑑 2 + 𝑙 2 )3/2 . 107

The moment m of the bar magnet is calculated assuming the

value of B𝐻 .
 Observation
Length of the magnet 2l = ___________ cm
l = ___________ = ___________
Distance between the null point N1 and N2 = ___________
d = ___________ cm = ___________
The horizontal intensity of the Earth's field at the place
B𝐻 = ___________
Moment of the magnet m = B𝐻 = (𝑑 2 + 𝑙 2 )3/2 . 107
= ___________
 Conclusion
Me and my group were successfully able to study,
document and understand the magnetic field lines around
a magnet using the technique of magnetic field mapping.
It helped in having clarity in the concepts of
• field lines
• magnetic field lines around a magnet
• the influence of the earth's magnetic field lines
around a magnet
• the concept of null points
etc…